Context:
The Madras High Court, in a recent decision from June 2024, overturned a conviction under the Protection of Children from Sexual Offences (POCSO) Act, 2012, bringing to the forefront the ongoing debate about the reliability of DNA profiling in legal settings. The court’s ruling emphasized the importance of not solely depending on DNA evidence for securing convictions and underscored the necessity for additional corroborative evidence to ensure fairness and accuracy in the judicial process.
Relevance:
GS II: Polity and Governance
Dimensions of the Article:
- Overview of DNA Profiling
- Legal Applications of DNA Profiling
- Limitations of DNA Profiling
Overview of DNA Profiling
- Definition: DNA profiling, also known as DNA fingerprinting, is the process of identifying individuals by examining specific areas of their DNA. Despite the fact that human DNA is overwhelmingly similar (99.9% identical), the critical 0.1% comprises Short Tandem Repeats (STRs), essential for forensic analysis.
- DNA Structure: DNA, the hereditary material, is located within the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells, forming a double helix configuration.
- Chromosomal Arrangement: It is segmented into 23 chromosome pairs, received equally from each parent, encoding genetic data through sequences of nucleotides—Adenine (A), Guanine (G), Thymine (T), and Cytosine (C).
- Sample Collection: DNA is harvested from biological substances like blood, saliva, and semen to create profiles. ‘Touch DNA’ collected from physical contacts often provides insufficient material for effective profiling due to possible contamination.
- Profiling Focus: The process emphasizes specific DNA segments known as genetic markers, predominantly STRs, notable for their distinctness among individuals except in identical twins.
DNA Profiling Methodology
- Extraction: DNA is isolated from collected biological specimens.
- Purification: The extracted DNA is purified to remove any contaminants and its concentration measured.
- Amplification: Specific genetic markers are replicated to produce adequate DNA quantities for detailed analysis.
- Analysis: The unique sequences within the DNA markers are identified.
- Comparison: DNA profiles are compared to determine a potential match by evaluating the probability of similarity.
Special Considerations in DNA Profiling
- Degraded Samples: For samples that are environmentally compromised, miniSTRs, which are more resistant to degradation, are utilized. Mitochondrial DNA (mtDNA) is also employed for maternal lineage tracing when nuclear DNA is inadequate.
Legal Applications of DNA Profiling
- Forensic Analysis: DNA profiles derived from crime scene evidence are matched against known references to determine three possible outcomes:
- Match: Profiles that are identical suggest a single source.
- Exclusion: Differing profiles imply different origins.
- Inconclusive Results: Sometimes, the data does not yield clear conclusions.
- Statistical Analysis: Matches do not definitively establish identity but provide a statistical likelihood, expressed as a “random occurrence ratio,” which estimates the frequency of the DNA profile within the general population.
- Legal Implications: As emphasized by the Madras High Court and the Law Commission of India, a DNA match alone is insufficient for conclusively proving identity or guilt beyond a reasonable doubt due to the potential commonality of DNA profiles within the broader population.
Limitations of DNA Profiling
- Environmental Vulnerability: DNA samples can degrade due to environmental factors, resulting in incomplete profiles.
- Analytical Techniques: Methods like miniSTRs and mtDNA are alternatives for compromised samples, yet they have inherent limitations.
- Process Complexity: The precision required in DNA profiling means that contamination, mishandling, or procedural delays can undermine the accuracy of results.
- Cost Concerns: The high cost of DNA analysis can restrict its availability and application.
- Judicial Consideration: DNA evidence, while powerful, is not foolproof and must be evaluated alongside additional evidence to ensure equitable legal judgments.
- Legal Framework Gaps: Current laws acknowledge the use of DNA in legal settings but do not provide a thorough regulatory basis.
DNA Regulation Legislation
- DNA Technology Regulation Bill, 2019: This bill, which has been presented multiple times in Parliament, seeks to refine the regulatory context for DNA technology. It has sparked debate regarding the accuracy of DNA techniques, privacy concerns, and the potential for misuse.
-Source: The Hindu
